Brake for trailers



Dem-12,1939. o. E. E. s'rRolvual-:RG`

BRAKE FOR TRAILERS 2 sheets-sheet 1 Filed Feb. 10, 1938 .afin 1fave/@Zar I IV'" Dec. l2, 1939. o. E. E. s'rRoMBERG" BRAKE FOR TRAILERSFiled Feb. 10, 1938.

2 Sheets-Sheet 2 man@ Patented Dec. 12, 1939 UNITED sT-Aras PATENToFFlci-:-

01o!A E. E. Stromberg, Chicago, Ill. Application February 10, 1938,Serial No. 189,711

14 claims.

My invention relates to improvements in brakes for trailers and thelike. 'I'he invention is primarily adapted for use with house cars andsimilar trailers which are'aided by ordinary passenger f automobileshaving hydraulic brake systems though the mechanism which I propose touse might under some circumstances bez equally well used with pneumaticoreven mechanical brakes by making simple and obvious changes in thestructure.

One object of my invention is to provide on an automobile and on atrailer two-seplatrate` hydraulic systems which maybe connected andconnection will automatically apply the brakes on the trailer. Otherobjects ofmy invention -will appear :from time to time throughout thegrammatically in. the accompanying drawings,-

specification and claims.

My invention is illustrated more or less dia- Figure 1 is a layout inplan view of the hydraulic system showing thevehicle and vtrailer indotted lines;

Figure 2 is on an enlarg'd scale showing the coupling be- `Figure 3;

Figure 6 `is .a side elevation in part section showing the connectionuncoupled.

-Likeparts are indicated by I like-characters throughout thes'peciiication and drawings'.

' I is 4a master'brake cylinder having .a piston rod 2, and a lever 3,adapted to be rotated to pushthe Ipiston rod and thepiston containedwithin the 'master cylinder forwardly in response e. to pressure on thebrake levei` l. 5 is a hydraulic pipe-connectingy the master cylinder I,withv the@l theleit limited by engagement with the aperfront wheelhydraulic pipe 6 and the rear wheel turedplug 33 in the end of thesleeve 3l.. The

a side elevation in part section A the `piston "2l, and projecting atits other end (cl. 18s-f3) y hydraulic pipe l. 'I'he pipes 6 and 1connect to the usual type of actuating pistons not shown associated withbrake drums 8, on front and rear wheels. 'I'hisA is just the usual typeof hydraulic transmission characteristic ofl the type 5 of automobileson the -road today. 9 is a trailer brake pipe extending from the pipe 5,rearwardly. to a socket IIlmounted on the rear automobile cross memberIl, supported on the rear ends of the frame l2. l 1' 10 I3 is Ya trailerhitch support mounted on the rear ends of the frame members I2, andadapted to support a trailer hitch of any suitable type. I I, is a pipeassociated with brake cylinders not shown in brake drums i5, on thetrailer wheels. l5 This pipe I4 is connected by -means of a pipe I 6,to`a trailerv master cylinder l1. Associated with the master cylinderI1', is an oil reservoir I8, the whole bolted as at I9, to a part of thetrailer frame 20. 2| is a masterplunger mount- 20 -ed for reciprocationin the cylinder Il. 22 is a spring tending to move the master plunger tothe leftto release brake pressure in the trailer. 23 is a safety valvewhich is held by the spring 24 against a seat as indicated in Figure 3.When the plunger 2l is moved to the right, hydraulic liquid in thecylinder I1 is forcedvacross the seat oi!l the valve A23 compressing thespring 2 4 and allowing the hydraulic iiuid .to pass into the pipe I6,to apply the brakes on the trailer. `If there 30 yshould be a breakagein that part of 'the system;

.beyond the valve 23, then the valve-23 would,

Mby the too sudden rush oi' hydraulic iiuid, be moved' further to theright into the cylindrical valve seat 25, to prevent excessive escape ofdfluid from the system. Under normal circumstances, this valve 23, hasno effect on the operation of the apparatus. 26', is a filler cap forthe oil reservoir and ports 2l insure that the hydraulic braking systemwill always" be kept full, the ller cap 26, providing anair chamber. Thespace behind the piston 2l is kept full of oil which enters through theport 2l, make up oil can pass around the piston` and when the pistonmoves to the right the brake is applied.

'I'he piston ,21, is mounted on a hollow guide sleeve 29 slidable inthe`cylinder I1. 30 is an operating pin in' eilect a piston rod,socketed at one end inthe sleeve 29, immediately behind outwardly beyondthe. sleeve 3l, which is a prolongation of the cylinder Il. 32 is a pinrigidlyV mounted ori the member 30. Movementtoward spring 22, tends toforce the piston 2|, the sleeve 28, andthe pin 30 to the left.

34 is a spring within the sleeve 3|. It abuts at one end on the innerend of the plug 33, but is out of contact with the pin 38, and abuts atthe other end on an apertured sleeve 35,l slidable in the sleeve 3|.

radially opposed trunnion pins 35, extending out '1 abutment 41 on theoil reservoir I8, to hold the 20. the links 38 to compress the spring 34and hold I provided at their other ends with inwardly ex tending pins 50which are .adapted to engage sure in the brake system will force theplunger lever 44 in the position shown in Figure 3. When that is thecase, the lever exerts a tension on the sleeve 35 in the position shownin Figure 3 with the plunger 2| in the inoperative position, that is inthe position in which the brakes are not applied. When the latch isreleased -the lever rotates into the position shown in Figure- 6allowing the sleeve 35 to be forced inwardly by the spring 34 moving thepiston 2| to the right and thereby applying the brakes on the trailer.50 is a flexible hydraulic hose connected 'at one end to the socket I0and at the other end to the coupling socket 5|. This couplingsocket isof substantially the same diameter as the sleeve 3|. It contains aspring 52, a piston 54 forced outwardly or to the right as in Figure 3by the spring 52 limited in its outward movement by the spring lock ring55. 5|iis a.ller hole in the wall of the coupling sleeve 5|.l 51 is ayoke joining two links 58, which links are pivoted on 'pins 53 on thesleeve 5| and are locking grooves 5| on the two arms of the lever 42. Inthe position shown in Figures 3, 4 and 5, the pins 50 engage the grooves5| and the lever is in the locked position. Under thesev circumstancesthe piston 2| is free to move in the cylinder l1. The piston 54v is freeto move in the sleeve 5| andthe pistons 54 and 2| are connected by thepin 30 under compression. The pressure on the spring 52 and in thevhydraulic system on the automobile is sufilcient to force the pin 30slightly to the right to disengage the collar 32 from its contact withthe plug 33 so that the parts are all free and iloating. Under thesecircumstances when the operator of the automobile applies the brakes,the hydraulic pres- 54 to the right. The mechanical connection embodiedin the push pin 30 will force the master cylinder 2| of the trailersystem to the right and apply the trailer brakes. When the automobiledriver releases the brakes, pressure in the automobile system will falland the spring 22 will force the piston 2| to the left and force thepiston 54 to the left releasing the brakes on the trailer simultaneouslywith the release of the brakes on the'automobile. 62 is a. safety cableengaged at one end on a bracket 63 at the rear end of the automobile andat the other end on the end of the latch handle 46. This cable 62 isshorter than the pipe' 50 but both are long enough so that as long asthe coupling between the automobile and the trailer is not discon- Thissleeve 35, hastwon nectedthey hang loose and are under no tension nomatter what the relation position of the two vehicles. It, however, itshould happen that the trailer hitch should let go and the trailer ceaseits forward movement while the automobile continued the cord 62 willcome under tension before any tension is applied to the tube 50.'

Tension on the cord 52 will rotate the latch handle 46 and release thelatch whereupon the spring 34 will move the sleeve 35 to the rightrotating the lever 42 in a counter-clockwise dlrection to permit the pin50 to disengage from the notches 5| so rthat the coupling sleeve 5| willbe disconnected from the trailer.

When this happens the spring 52 will force the piston 54 from theposition shown in Figure 3 back to the position shown in Figure 6against the lock ring 55 thus slightly increasing the volumetriccapacity of the hydraulic system on the automobile but merely requiringa slightly further movement of the brake pedal by the operator to applythe brakes of the automobile and there will be under these circumstancesno leakage of hydraulic iluid from the automobile system. At the sametime the spring 34 which has pushed the sleeve 35 to the right willapply a pressure to the sleeve 23 and so to the piston 2| and therebyapply the brakes on the trailer, again without any loss of hydraulic.iiuid from the trailer system. The slots 33 permit the lever rotateeven further the pins sliding in the sleeve 39 so that the lever canswing down freely without interference.

I claim:

l. A braking system for automobiles and trailers and the like comprisinga fluid brake system on the automobile, a master cylinder associatedwith such system and adapted to be controlled by the operator, a iluidvbrake system on the trailer, a master cylinder associated therewith, aconnection between the master cylinder on the automobile and the mastercylinder on th'e trailer whereby when the brakes are applied bymanipulation of the master cylinder on the automobile, the pressuregenerated in the automobile system causes manipulation of the mastercylinder on the trailer to apply the brakes, an automatically releasableconnection between the system on the .trailer and on the automobile, andmeans responsive to excessive separation of trailer and automobile forreleasing such connection.

2. A braking system for automobiles and trail-l ers and the likecomprising a uid brake system on the automobile, a master cylinderassociated with such system and adapted to be controlled by theoperator, a iiuid brake system on the trailer, a master cylinderassociated therewith, a connection between the master cylinder on theautomobile and the master cylinder on the trailer whereby when thebrakes are applied by manipulation of the master cylinder on theautomobile, thegpressure generated in the automobile system causesmanipulation of the master cylinder on the`trailer to apply the brakes,an automatically releasable connection between the system on the trailerand on the automobile, means responsive to excessive separation oftrailer and automobile for releasing such connection, and means ontrailer and automobile A,for closing the released ends of the uidconnection automatically when they are disconnected.l

3. In a brake system, a master cylinder, a

e aisas'n in continuation of the cylinder, a piston rod ex`` tendingoutwardly beyond the end of the sleeve.'` means for limiting the outerexcursion of the rod, a connection cylinder and means for -releasablylocking it in alignment with the rst mentioned sleeve, a piston therein,a fluid connection to one side of the piston, and yielding means,operative upon the separation of the sleeve and connection cylinder fordisplacing the piston in the connection cylinder'to exert a -pres-. surein, the iiuid connection, the piston being adapted to engage the end ofthe piston rod when the cylinder and sleeve are connected.l

4. In a brake system, a master cylinder, a piston mounted forreciprocation therein, a sleeve in continuation of the cylinder, apiston rod extending outwardly beyond the end of the sleeve, means forlimiting the` outer excursion of the (rod, a connection cylinder andmeans for releasably locking it in alignment with the rst mentionedsleeve, a piston therein, a uid connection to one side of the piston,the piston being adapted to engage the end of the piston rod when thecylinder and sleeve are connected, Aa releasable latch adapted to holdthe cylinder and sleeve4 together, and a brakable tension member adaptediirst to release the latch and then to operate the master cylinder toapply the brake.

5. A fluid brake system including a master piston, a latchassociatedwith the cylinder and necting cylinder in alignment with themasterv lease the spring whereby it forces the piston adapted toreleasably engage the connecting cylinder and a connection betweenthelatch and the spring adapted' when the latch is in the connectingposition to compress the spring, and when the latch is in thedisconnected position to rethetwo cylinders together and a connectionbetween the latch and the spring adapted whenl the latch is in -theconnecting position to compressA the spring, when the latch is in thedisconnected position to release the Spring. whereby it mayforce thepiston into brake applying` position.

7. A -iiuid brake system including a master cylinder,` an operatingpiston, A'a piston rod, `a closure for one end of the cylinderencirclinglthe' piston rod, and means for limiting the outward excursionof the rod through the closure, a concylinder, a connecting pistontherein, adapted to engage the free endof the piston rod, a springinterposed between thescylinder closure 'andthe piston, a latchassociated with the cylinder and adapted to releasably engage theconnecting cylinder anda connection betweenthe latch and into i nectingposition to compress the spring, and when the latch is inthedisconnected position to release the spring whereby it forces thepiston piston rod. 8. In combination, two vehicles, a iiuid brake systemon each, a coupling between them, a

master cylider on one vehicle and a connection cylinder on the other, anoperating piston and ,a piston rod in the master cylinder, a closure for-one end'of the vcylinder and means for limiting the outward excursionof the rod therethrough, a connecting4 piston in the connecting cylinderadapted to'engage the free end of the piston rod, a spring interposedbetween the cylinder closure and the piston, a latch adapted to hold thetwo cylinders together and a connection between the latch and the springadapted when the latch is in the connecting position to compress thespring, when the latch is in the disconnected position to release thespring, .whereby it may force the piston into brake applying position,and means' for limiting the outward excursion of the connecting pistonwhen it is released from contact with the'piston rod.

9. A iiuid brake system' including a master cylinder, an operatingpiston, av piston rod, a closure for one end of the cylinder encirclingthe piston rod, and means for limiting ,the out- `ward excursion of therod through the closure, a

connecting cylinder in alignment with the master cylinder, a connectingpiston therein, adapted to engage the free end ofthe piston rod, aspring interposed between the cylinder closure and the piston, a latchassociated with the cylinder and adapted to releasably engage theconnecting cylinder and a connection between the latch and the springadapted when the latch is in the connecting position to compress thespring, and when the latch is in the disconnected position -to releasethe springwhereby it forces the piston into the brake applying position,the connection between the spring and latch comprising an abutment-ringslidable in 'the master cylinder,

' the wall of the master cylinder, being slotted, a

trunnion projecting through said slots and a linkage between thetrunnion and the latch lever.

the spring adapted when the latch is in the con? l0. In combination, twovehicles, a iluid brake system on each, a coupling between them, amaster cylinder on one vehicle and a connection cylinder on the other,an operating' pistonl and a piston rod in the master cylinder, aclosurefor a connecting piston in the connecting cylinder adapted toengage the free end of the piston rod, a spring interposed between the.cylinder closure and the piston, a latch adapted to hold the twocylinders together and a connection between the latch and the springadapted when the latch is in the connecting position to compress thespring,

when the latch is in the disconnected position to release lthe spring,whereby it may force Athe piston intobrake applyingv position, theconnec-v tion between the spring and latch comprising an abutment ringslidable in the master cylinder, the wall of the master cylinder beingslotted, a trunnion projecting through said slots and a linkage betweenthe trunnion and the latch lever.

1l. -A fluid brake system including a master cylinder', an operatingpiston, a piston rod, a yclosure -for' 'lone end of the cylinderencircling '(5' 55 one end of the cylinder and means for. limiting.V Vthe outward excursion of the rod therethrough,

I the piston rod, and means for limiting the outward excursion of therod through the closure,

a connectig cylinder in augment with the mas-4 ter cylinder, aconnecting piston therein, adapted to engage the free end of the pistonrod, a spring interposed between the cylinder closure andthe ingposition to compress the spring, and when the latch is in thedisconnected position to release the spring whereby it forces the pistoninto, the brake applying position, and means for limiting the outwardexcursion of the connecting piston when it is released from contact with'che piston rod, the latch comprising a lever, a locking cam therefor,and a connection between said locking cam and the opposed vehicle, apipe between the fluid system on the vehicle carrying the connectingcylinder, the connecting cylinder long enough to reach to the othervehicle and a connection between such vehicle and the latch shorter thanthe pipe connection.

12. In combination, two vehicles, a fluid brake system on each, acoupling between them, a master cylinder on one vehicle and a connectioncylinder on the other, an operating piston and a piston rod in themaster cylinder,A a closure for one end of the cylinder and means forlimiting the outward excursion of the rod therethrough, a connectingpiston in the connecting cylinder' adapted to engage the free end of thepiston rod,

a spring interposed between the cylinder closure and the piston, a latchadapted to hold the two cylinders together and a connection between thelatch and the spring adapted when the latch is in the connectingposition to compress the spring,'

, hicle carrying the connecting cylinder, the connecting cylinder longenough to reach to the other vehicle and a connection between suchvehicle and the latch shorter than the pipe con- 5 nection.

13. A uicibrake system, including a master cylinder, a piston therein, ahydraulic brake system and a spring adapted to force the piston normallyin a direction opposed to its movement l0 for brake application, aclosure for one end of the master cylinder, a piston rod associated withthe piston and projecting outwardly through the closure, means onclosure and rod interlocking to limit the outward excursion of thepiston and 15 piston rod, a spring between the closure and the piston, asliding spring abutment in the cylinder,

ia connection sleeve and means for` yieldably latching it against theend of .the master cylinder,

a piston in the connecting sleeve abutting against 20 th end of thepiston rod, and means for subjecting the opposed end of said pistonv toiiuid pressure, a latch lever adapted simultaneously to lock the sleeveand cylinder together, and to force the spring abutment ring in adirection 25 opposed to brake application, means for locking the leverin position, means for releasing the lock to permit the spring to rotatethe lever, and' to force the piston outwardly to apply the brakes.

M In combination, two vehicles coupled to-/ao gether, an operatorcontrolled fluid actuated braking)` system on one, a separate uidactuated braking system o n the other, two aligned cylinders oneassociated with each braking system, releasable means' for holding thecylinders in end 35 to end relationship, a piston in each cylinder exposed-on one side to its respective fluid braking system, a mechanicalpressure connection between the two pistons, yielding means associatedwith' the piston in the second mentioned braking 40 system tendingnormally to force it in a direction to apply braking pressure and meansassociated with the releasable means for rendering said yielding meansinoperative while the releasable means hold the pistons together.

OLOF E. E. STROMBERG'.

